I was pressure washing my block yesterday and I think I damaged the oil pressure relief valve. I'm not sure though.

It looks like a press fit piece with a spring and there's a diaphram below the spring. In the pictures in Santucci's book, it appears that the fiber diaphram piece is supposed to be on top of the spring closer to the oil filter than the oil passage. Which way is right?

Also, I have not be able to find a replacement valve in the event that mine is damaged. Is there a source? I have noticed that in Santucci's book he says it could be drilled and tapped for a plug... is there a benefit to that for long term street use?

Thanks

i have taken mine out. it is for use if operating in extreme cold weather and thick oil associated with it. in normal operation it is not needed.

it can allow unfiltered oil to bypass the filter and dirrectly go into the engine ports. i have taken mine out and installed a frost plug of the correct size. the kind you hammer in. tom

Anytime you have 100% filtered oil is a good thing! Change your oil at regular intervals just like normal. On break-in, after 100 or so miles,sooner if you want to, cut the filter open and "scare" yourself. Just think how much of that trash could have recirculated through engine, had you not blocked off the bypass valve!

The part has been discontinued. But, I was able to extract the valve with minimal damage. I think I can reassemble it and re-install it.

I live in Ohio, but rarely would go out in the snow with this car. Is it worth re-installing, or just leave it out while I'm at it?

100% filtered oil sounds great, but the engineers put it there for a good reason.....

Tom is yours a street only motor?

Thanks.

yes, mine is a street engine. atleast 99% of the time. do not put a damaged valve back in. you will not get oil filtration. just plug the hole with a plug either threaded in or like mine, frost plug design. 100% filtration then. tom

I agree, the engineers im sure thought that the bypass would act as some sort of a double redundant system should a problem arose in the oiling system and need to bypass the filter altogether to at least maintain oil pressure and limp home! But I think most of us will agree that should an issue in the oiling arise to block the filter causing the oil to continue unfiltered,bypassing it throughout the engine, the damage is already done!

I dont know if this is what you are looking for but Melling Engine Parts has an online catalog. You can download the whole 24MB PDF or get it in bits and pieces. The Oil Pump Pictures is 7MB
http://www.mellingengine.com/Catalog.aspx

Part Lookup by Manufacturer - GMC-Chevy Trucks is only 207 KB
Look on line 45... it says go to line 18 but go to line 45

At the bottom of the catalog page you can look at either
Oil Kits Photos - 7 MB PDF or Oil Pump Photos - 7 MB PDF

Pinbluff- didn't see anything that resembles this part in those catalogs.

There was minimal damage to the piece, just a little bent. What happened is that the high pressure water forced the diaphram past the spring to the bottom of the passage. If I didn't notice it, I'd have 100% filtration by accident. haha




I fixed the part and tweeked it all back to proper shape and round. Reassembled the spring and diaphram. Should be fine to run, but I think I'll take everybody's advice and just install a freeze plug.

I would install a pipe plug NPT

IIRC,(if I remember correcly) you do not need to drill the hole any larger,just find the correct size pipe tap & install a pipe plug.

MBHD

1/4" pipe tap will do the trick. I started to suggest it earlier, but he seemed content on trying to fix the valve instead of pluggin' it.

It is bigger than a 1/4" tap ,I have one in my garage but a little lazy to go see what size it is,unless someone needs to know?

MBHD

Yep, your right I was thinking Small Block and Big Block oil filter housing modification.

by my measurements should be somewhere between 11/16" and 3/4".

Thanks for the pics of the oil pump. I am saving up to rebuild my motor so maybe now I will recognize all the parts.
There are so few pics online of Inline motor guts we need all the help we can get.

well, it's not exactly the oil pump. It's the oil filter mounting area on the outside of the block. The smaller hole to the right is the one that comes from the oil pump. The oil pump is mounted to the block underneath the pan.

Get Santucci's book, you'll be much better off and there are plenty of pictures.

I just sent off a money order for Leos book today.
Gee I have never been excited about reading before.

It's got a lot of good stuff in it. It does lack some info, but that info can be made up for using "Engine Builders Handbook" by Tom Monroe, or using a Motors or Clymer manual from that era.

Leo's book is about as close as you'll come to getting lots of detail about the inliners. My only complaint is that sometimes there isn't text that explains some pictures. It also glazes over some of the more basic stuff. So hopefully, you have had some engine experience in the past. All in all, the book is worth its weight in gold if you mess with these things.

Some engine experience Yes. but like many others I was Bottle Fed on the Small Block Chevy.
Working on the Six will be like... when you come home and the old lady has re-arranged the furniture...
Its all there but you dont know where to sit your glass.

"Bottle fed", what a waste. At least you didn't cut you teeth on SBCs. you'd need braces to get the back "inline". Have fun, and Santucci's book is great!